CO-Horts

CO-Horts

Monday, July 28, 2014

One of the amazing things about Colorado is its variable terrain, which encompasses several life zones from the grassy plains to the high alpine tundra. While many of our gardens are starting to wind down in the lower elevations, up high the flowers are in full bloom. Below are some photos taken from a recent hike along the 4th of July Trail to Diamond Lake in Boulder County. Hopefully this inspires you to get out and enjoy the height of wildflower season in the higher altitudes.

Common Name: Scentbottle
Scientific Name: Limnorchis dilatata
Look for this little beauty near water. These were located on along a hillside stream.

Common Name: Colorado Columbine
Scientific Name: Aquilegia coerulea
It isn't any wonder that this columbine was chosen as the state flower. "Columbine" is Latin for dove, a name chosen because of the graceful appearance of the flower. "Coerulea" refers to the blue color of the petals.

Common Name: Pink Pussytoes
Scientific Name: Antennaria rosea
Who can resist a plant with a name like "pussytoes"? As the name suggests, the blooms resemble the toes of a cat. Pussytoes can be found in local nurseries and, due to their mat-forming habit, make a wonderful groundcover.

Common Name: Monkshood
Scientific Name: Aconitum columbianum
The showy "hood" of this flower resembling a monk's cowl can be deep purple to blue to greenish white. Flowers are visited by hummingbirds, bumblebees and hawkmoths.

Common Name: Wooly Thistle, Mountain Thistle, Frosty Ball
Scientific Name: Cirsium scopulorum
Thistles have a bad reputation, but most of the thistles found in Colorado are natives and are an important source of pollen and nectar for native bees, they provide food for many species of butterflies, and thistle seeds are a favorite of finches and other birds. For more information about thistles in Colorado, check out Thistles of Colorado: Identification and Management Guide, which was produced by the Larimer County Weed District.

Thursday, July 24, 2014

It seems that the summer of 2014 has been the "best year ever" for fire blight. I've never seen it so much and for awhile, our Extension Office phones were ringing off the hook about people seeing brown branches and crooked twigs from this bacterial disease. Fortunately CSU has a very good Fact Sheet on the subject.

If you haven't seen fire blight, it's characterized by the tip of the branch curling over, resembling a Shepard's crook:

The Shepard's crook of fire blight

If you look further down the branch, most of the leaves will be brown and you'll see a distinct darkening along the stem where the canker has infected tissues:

The bacteria turns the branch/stem a dark brown/black color

So what is fire blight? Well, as I mentioned, it's a bacterial infection caused by Erwinia amylovora that only occurs on plants in the Roseaceae family (apples, crabapples, mountain-ash, hawthorn, etc.). Remember, the Roseaceae family is one of the largest families in our landscapes, so it can affect a number of plants.

Infection can occur in a number of ways...through cracks in the bark or pores in leaves, on insect bodies, by splashing of the spores via rainfall or irrigation and through other natural openings. There seems to be a correlation between fire blight and hail-damaged trees from the previous summer. The bacteria kills cambial tissue (where the xylem and phloem are located) and continues to move down the branch.

Everything brown on this tree is fire blight

It's important to note that the tree will try to ward off the spread of the bacteria. Some species and cultivars are better at doing this than others. While a tree may be labeled as "resistant" to fire blight, it can still get the bacterial infection, but it's better at "sealing" off tissues to stop infection. The bacteria survives winter inside infected tissues and tends to ramp up during warm, wet springs. There is generally bacterial ooze associated with this disease.

So what can you do? Well, the best control is to plant resistant varieties. But that's easier said than done. You can prune out infected tissues during the growing season, but it's crucial that you sanitize your pruning tools betweeneach and every cut. That means you have to spray them with Lysol or Listerine or dip them in a 10% bleach solution. Does this sound like a pain to you? It is. I've done it.

Or you can live with the ugliness of the tree this summer and prune out infected areas during the dormant season. By waiting, you don't have to sanitize. But you have to wait.

Regardless of when you prune, the current recommendation is to cut 8-12" below the edge of visible infection. This is a lot of extra branch you're taking off. And if the infection has moved into the main trunk of the tree, it's best to make a final pruning cut at the base.

For a personal anecdote, I was just at the Gardens on Spring Creek in Fort Collins. One of their apples was absolutely annihilated with fire blight. The director and the city forester were discussing the tree and they came to the conclusion to remove the tree. After making all the pruning cuts to remove the infected branches, the tree would have looked unsightly and wouldn't resemble the proper shape.

There are some pesticides that can be used, both as a dormant control and during flowering. The University of Minnesota Fact Sheet has information on the various types of pesticides that can be used to prevent new infections.

Tuesday, July 22, 2014

Guess what? You might actually be seeing crabgrass in your lawn this time of year! It was late germinating this spring (we didn't see it in Fort Collins until late May), but now it's large and in charge. This is crabgrass in late May:

Young crabgrass

Now it looks like this (late July):

Small (smooth) crabgrass (Digitaria ischaemum)

Small (smooth) crabgrass--growing in concrete!(That's a joke)

Small (smooth) crabgrass near sidewalk

Crabgrass seedhead

Many think they have crabgrass, but they don't. Here are some other crabgrass look-alikes that are often called crabgrass, but misidentified...

This is not crabgrass; this is bromegrass (wide, coarse blade; often a "W" watermark on upper tip of leaf):

Bromegrass in a bluegrass lawn

This is not crabgrass; this is annual bluegrass (characteristic apple green color; often with seedheads):

Annual bluegrass in a Kentucky bluegrass lawn

And this is not crabgrass; this is tall fescue (clumps of grass with rough edges on the leaf blade):

Tall fescue in a bluegrass lawn

This isn't crabgrass either; this is orchardgrass (flat "stems" and tall white ligule):

Crabgrass is characterized by its prostrate growth habit, especially after mowing and a light, apple green leaf color. The seedheads are digitate (finger-like) and will begin forming in earnest in August. Crabgrass is a warm season grass (and a summer annual), so it will die with the first frost.

If you want to control it now, use any herbicide product containing quinclorac (such as Ortho Weed Be Gon Max Plus Crabgrass Control, Fertilome Weed Out Plus Q or Bayer All-in-One Lawn Weed and Crabgrass Killer). Be aware it may take more than one application to completely kill this persistent weed. It's much easier to control when it's a seedling or use preemergence products in early spring.

The big point to make, with the exception of foxtail and crabgrass, is that quinclorac will not work to selectively remove tall fescue, bermudagrass, bromegrass or annual blugrass from your lawn. So identification of grasses that LOOK like crabgrass is essential before you start spraying herbicides willy-nilly.

Wednesday, July 16, 2014

Note:
While this entry is about entering cookies at the county fair, it could be
entering anything, from the dinner-plate dahlia to biggest zucchini to strawberry jam. County Fairs tend to bring out the competitor in all of us in a
desire to win the elusive blue ribbon.

It is 14 days and counting until I come before “The Judge”. It’s almost Larimer County Fair time, which
means it’s time for cookie judging. You
might think winning blue ribbons would be easy for someone who’s been baking
for six decades. Well, it’s not—because my
family members are not the judges.

The Fair judges are professionals with consumer science
degrees, experience and a list of eight (!) criteria which must be met “…to the
letter of the law” (judges’ instructions).
They take their instructions seriously, and even the audience of highly
qualified cookie monsters cannot convince them that a medium size cookie is
larger than 2 ½ inches!

I start preparing for next year’s fair the very same day
as judging. Why so early you ask? Well, if you really want to win blue ribbons
or champion ribbons, you need to pay attention to the judges’ remarks as to how
your current entry did or did not meet the criteria. Besides, it is always ego-building to hear
the judges argue as to why your entry deserves the Champion Ribbon. It’s not about the $2.00 premium awarded for each blue ribbon, it’s all about the “prestigious honor”—at least that’s what all my
taste testers say when I complain about how much I spend on groceries making
the winning entry. (Personally, I think
they just enjoy having the treats!)

Here is what I’ve learned about my chocolate chip trial
recipes this year: First, adding almond
butter to the basic recipe makes the cookies lighter, but they are dry and are
not “characteristic” of a chocolate chip cookie (characteristic is one of the eight criteria). Secondly, using cake flour instead
of all purpose flour yields a 6” cookie which cannot be removed from a hot
cookie sheet, because it has the consistency of a wet paper towel. Finally after using four bags of chocolate
chips trying new secret ingredients, my entry will be using last year’s recipe,
but making the cookies the correct size.

So, today I’m left wondering, “When the outside
temperature is 95 degrees, why am I still heating the oven to perfect
recipes?” Prestigious, competitiveness, or
just plain nuts….you be the judge! I know I'm not the only one out there who enters the fair. What do you plan to enter this year?

Thursday, July 10, 2014

Let me start by saying that I’m sure there are places for
Russian sage in the landscape.They are
tough plants and I’m told they are very unappetizing to deer.It’s just that I’m sick of seeing their
leggy, sprawling and spreading forms in every hell strip, median, shrub border
and foundation planting along the Front Range.Plus, my neighbor has one along our shared fence and it’s continually
trying to colonize my yard- oh the indignity.

Russian sage suckering its way under my fence

So I thought I might try and encourage a little diversity by
highlighting some similar plants that are a little better behaved and, at least
to my eyes, more attractive.There are
actually quite a few smallish shrubs or shrub-like plants that have similar ornamental
attributes to Russian Sage.

Blue mist spirea (Caryopteris
incana and Caryopteris × clandonensis)-

﻿

Blue Mist Spirea Flower

Blue mist spirea has very similar flower color and timing to
Russian Sage.However, it lacks its sprawling
and uneven habit and though it will occasionally come up from seed it does not
spread nearly as aggressively. The remnants of its fruit also add texture to a landscape in the winter months. They are
fairly common and easy to find.

Blue Mist Spirea Winter Texture

Mojave sage (Salvia
pachyphylla)-

This sage develops showy purple flowers mid-summer.The foliage is fragrant and semi-evergreen
remaining silvery-green late in the fall and early winter.Once established, plants require little water
and in our demonstration garden tend to struggle during wet winters.

Inflorescence of Mojave sage late in the summer

Lead Plant (Amorpha
canescens and A. fruiticosa)-

Lead plant

There are two species of lead plant commonly grown along the
Front Range, A. fruiticosa and A. canescens.Both are attractive landscape plants which
develop purple flowers midsummer and have blue green foliage.A.
fruiticosa is the taller of the two species.They are low water use once established and are tolerant of infertile
soils.They are native to the plains and in my opinion seem to fit more naturally into western landscapes.

﻿

Lead plant flower

Newly planted lead plant

Catmint- (Nepeta sp.)-

Catmint

There are a number of different species, hybrids and clones
of catmint.They come in a variety of
different heights and several flower colors, but most of those which are common
to Front Range landscapes have purple flowers which provide color throughout
late spring and summer, especially when deadheaded. Catmint also attracts a variety of
pollinators and butterflies to the garden.

Monday, July 7, 2014

There’s a new Horticulture Agent in Douglas County, me.
There’s so much to learn, from my new environs to the new work routine. Then there
are all the garden questions from around the county, What’s this plant? What’s
that bug? In the last few weeks, the number of calls to our office is skewed
towards insects. In my county, I’m lucky. The Director, Joe Julian, is an entomologist.
When he’s not available to answer
questions about insects, however, they fall to me.

Even though I’m a newbie horticulture agent, I’m not new to
the question/answer routine in Extension offices. Before going back to school
for a Master’s degree, I was a Colorado Master Gardener (CMG) in the northern
Front Range for many years. So I have learned what most seasoned CMGs know,
there’s always something you don’t know and the challenge is figuring out the
problem.

Take for instance, a plant sample that was brought to the
CMG in the office a week ago. This sample
was from the terminal end of a Colorado Spruce and was dead. The homeowner
stated that it wasn’t just one young spruce in the landscape with this symptom,
it was 20. Ugh. My knee jerk reaction was to rattle off reasons for top dieback
in spruces, but the sample didn’t fit my usual responses.The new terminal growth was bent in a shepard’s
crook and the inner bark had been stripped leaving just the dead outer bark. There
were also sawdust covered oval patches with a larva inside.

White
pine weevil chip cocoons. (From Fact Sheet 5.606)

I was stumped. So I did what any new horticulture agent would
do: I went into my office and googled, ‘spruce terminal dieback, sawdust cocoon’
on my computer. Eureka! There I found an exact description of the symptoms from
CSU Fact Sheet 5.606: White Pine Weevil (Pissodes
strobi). Say, what? But the homeowner’s plant is a spruce! With all my
experience as a CMG, I had never come across this insect.

As I left my office to talk to the Master Gardener, another CMG
had arrived and was explaining to the first: Yes, this is the White Pine Weevil
and is a common problem in the Castle Rock area in young spruces. The adults
hibernate in leaf litter in the winter, then climb up the tree to the terminal
branch to feed a bit and lay eggs just under the bark. When the larvae emerge,
they feed under the bark, girdling the terminal tip. As the larvae mature, they
make their way down the terminal tip, and at some point decide they’ve had
enough and pupate, covering their bodies with sawdust. When adults emerge from
the cocoon, they feed a bit on needles and bark, then head down the trunk to
hibernate in the leaf litter until next season.

How could an insect that didn’t seem to bother the spruces of
urban Northern Colorado Front Range be thought of as ‘common’ just 70 miles
south? Thanks to CSU experts, the answer is ‘elevation’. In Ft. Collins,
Loveland and other Front Range cities, the elevation is around 5,000 feet. In
Castle Rock and Colorado Springs, the elevation is above 6,000 feet. Why would
a 1000 feet make a difference for this insect? Only it knows, and it isn’t
talking.

As I start my horticulture agent career, the same mantra
will prevail as it did when I was a Master Gardener: There is always something
you don’t know and the challenge (and fun) is figuring out the problem. Bring
it on, Douglas County, I’m ready for more challenges to come my way!

To find out more about White Pine Weevil, check out our CSU
Fact Sheet 5.606.